Automatic transfer switch system with synchronization control

Abstract

An automatic transfer switch (ATS) system and method of operating an ATS system to switch between first and second powers received from respective first and second power supplies, are disclosed. In one embodiment, the method includes sensing a first phase associated with the first power and a second phase associated with the second power, and determining whether the first and second phases have failed to become synchronized within a first time period. The method further includes providing a control signal at a second output port when it is determined that the first and second phases have failed to become synchronized within the time period, determining that the first and second phases have become synchronized in response to the control signal, and switching between the first and second powers once it is determined that the first and second phases have become synchronized.

Description

FIELD OF THE INVENTION[0001]The present invention relates to Automatic Transfer Switch (ATS) systems employed to control the coupling of power sources to a load.BACKGROUND OF THE INVENTION[0002]Automatic Transfer Switch (ATS) systems are widely used to control the delivery of power from two different power sources to a load in a variety of situations, both commercial and residential. For example, a private residence normally receives its electrical power from a utility company. For various reasons, however (e.g., location in a region prone to severe weather), the homeowner can desire a backup source of electrical power, so that comfort or at least habitability of the residence can be maintained during periods in which utility power is unavailable.[0003]Typically, a gasoline, diesel, propane or natural gas internal combustion engine-powered electrical generator, capable of generating three-phase power, is installed in or near the residence, and arranged to be connected to one or more...

AI Technical Summary

Benefits of technology

[0008]The present inventors have recognized that, although modern generators may be better able to maintain a constant speed of operation and thereby better able to maintain a power output having a constant frequency, such generators also typically can be controlled in their speed based upon external control signals. Consequently, the inventors have recognized that it would be possible to design an ATS system to monitor how long

Problems solved by technology

However, one cannot simply leave the backup generator permanently connected, in parallel with the utility power, to the residential electrical circuits.

Nor can one simply power up a backup generator and connect it to the residential electrical circuits, without first disconnecting the residential circuits from the power lines coming in from the utility.

Consequently, it may no longer be practical for an ATS system to wait until the generator power signal happens to come into phase with the utility power signal, since this may take an excessively long time.

Consequently, conventional ATS systems employed in conjunction with such modern generators may be incapable of providing desired switching between such generators and other power sources in a satisfactory manner.

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